GRPN is a graphical (GTK) reverse polish notation (RPN) calculator.
GRPN works with real numbers and complex numbers.  Numbers can be
displayed in 4 different radix modes, and complex numbers can be
displayed in either Cartesian or polar form.

General Math Functions: + - * / sqrt sqr pow neg
Exponential and Logarithmic Functions: log alog exp ln
Trigonometric Functions: sin asin cos acos tan atan
Numerical Bases: binary, octal, decimal and hex
